In order to ensure normal operation of a thyristor circuit, a discharging circuit can be included to provide a current charge loop for the thyristor circuit. As shown in FIG. 1, a conventional common active discharging circuit can include a resistor, a capacitor, a diode, a switch, and so on. However, this particular circuit structure is relatively complex with high product costs and power losses. In another discharging circuit of FIG. 2, resistor RB and capacitor CB can be series connected between a bus voltage and ground. This discharging circuit structure is relatively simple with few components. However, power losses resulting in high power consumption can occur due to the discharging circuit being always connected between the bus voltage and ground.